Wireless system



Mag,r 6, 1930. M. 055Mo@ WIRELESS SYSTEM Filed Nov. 50. 1925 ,Hummm iPatented May 6, 1930 UNITED `STATES PATENT OFFICE Y 'MENDEL OSNOS,BERLIN, GERMANY, ASSIGNOR TO GESELLSCHAFT FR DRAJIT- LOSE TELEGRAPHIE M.B. H. HALLESCI-IES, OF BERLIN, GERMANY, A. CORPORA- TION F GERMANYWIRELESS SYSTEM Application lecl November 30, 1925, Serial No. 72,132,and in Germany December 17, 1924.

The present invention provides means adapted to increase the sensitivityof systems comprising static frequency changers in telegraphy ortelephony with what is known as a keying or telephony choke, and theterm keying choke as hereinafter used will be broadly to a choke adaptedto control an alternating current by means of a direct current. For thisobject, conformably with the invention, the action of the keying choke`is aided favorably by the simultaneous influencing of the magneticstate of the frequency changer. riihis may be utilized proiitablyin suchcases where the paths of the control currents, both in the keying chokeas well as in the frequency changer, possess time-constants which aresubstantially immaterial. This is true when the keying choke accordingto my application Serial No. 64,245, led October 22, 1925, and thefrequency changer according to the disclosure in m U. S. Patent No.1,664,044, granted Marc 27, 1928, are both made of iron-enveloped copperconductors passed jointly by the high frequency current as well as thecontrolling current.

The accompanying drawings illustrate one embodiment of the ideaunderlying the invention, wherein Fig. 1 illustrates one of the circuitarrangements capable of carrying out the invention; i

Fig. 2 illustrates by a considerably enlarged view for clearness ofillustration a `section on the line 2-2 through the frequency changer t;and i Fig. 3 illustrates by a considerably enlarged sectional view asection through the keying choker d on the line 8-3.

Now to refer particularly to the drawings, the frequency changers areconnected by way of condensers C1 C1 with a primary circuit I, andthrough condensers C2 C2 with a sec- .ondary circuit II, and consistsin` this lcase of two like parallel connected parts tt, and the samebeing most suitably made of copper conductors enveloped by a coat ofiron as disclosed in my above named U. S. Patent No. 1,664,044. Thekeying choke consists of two like halves dd, each half being arranged inseries with the respective half of the trans former t. The choke alsopreferably consists of copper conductors surrounded by little iron disksconformably with applicai tion Serial No. 64,245, filed Gctober 22,1925.

The quadrangle which is made up of the two halves of the frequencychanger t?? and the two keying choke halves dd, is supplied with directcurrent intwo diagonale thereof, one diagonal receiving a constantdirect current from battery b through choke coil f, while the otherdiagonal is fed with current thru a control element m in the form of amodulator, key or a similarly functioning apparatus. To obtain fullpower in the antenna circuit (not shown) which may, if desired, becoupled to the secondary circuit II through any well known form ofcoupling means, the current in the controlling element m must be of avalue equal to that of the current in the battery Z2. If the twocurrents from sources b and m are of equal value it is clearly seen thatthese currents may be made to balance one another inside the halves ofthe frequency changer tt, so that there exists there no longer anyadditional magnetization of the iron by properly choosing the directionof the current flow from sources b and m. Under the above condition, inthe choke halves Zd the two currents become additive to one another, sothat on account of the high saturation in the iron the two choke halvesdd come into consideration neither as ohmic nor as inductiveresistances. For interruption of the aerial power the current of thecontrol element is disconnected, or, most preferably, reversed inpolarity, with the result that the two direct currents will then becomeadditive in the transformer l lUO The above features may be briefly setforth by stating that under a condition with the key or modulator mopen, so that the only direct current saturation in chokes delk andfrequency changers tu is from battery c, the chokes Zet arepf relativelyhigh impedance because the direct 'current supplied as insufficient tobring the saturation of th'e'iron upto theopoint Acfco-mpl-e-te magneticsatu' ratio-n. On the other hand, the frequency changers t will be of arelatively low 1mpedance since the iron in them becomes saturated with asmaller amount of direct current and can' even be brought up tosaturation by the alternating current from the input side I, eine@ it ispossible to @empre-,ely saturate lthe iron Wrapper of the frequencyy'changer 'monica which will hold even Vif the direct Y 'current isinsufficient to carry the point of f cethreugn the frequency Ichangersatu'ratfifcn Well up beyond the knee of lthe 'saturation curve. It musthere he noted, however, that the harmonics developed tend to be'die'rent in accordance 'with whether the direct or alternati-ng currentproduces the magnet-ic saturation in the iron Wrapper.

Upon closing the key or modulation circuitmso that the direct currents'add the chokes `dal andv oppose in the frequency 'changers' a itisreadily 'seen that the effects will be 'opposite from those above statedwhich means 'that chokes'- del are of relatively lo'iv Aimpedance sincecurrents' from j?) and m are added in the keying chokes, the frequencychanger will be of relatively high impedance since currents from I) andm "oppose each otl'ier 'and are, therefore, neutralized, andl theharmonics developed Wil-'l tend to he odclsince they arethen producedbythe saturation of the vafl-ternating current, because vv'i'th cp'posing currents from b and m the iron Wrapper of the frequency cli-anger isnot-sa'turat'ed.IV

The thickness 'of the iron layer in lthe frequency changer 'is governedby the 'ivave length of the current supplied thereto. lhere the Wat/elengths are comparatively small, it is recommen'dableto "use a thinlayer, While when they are greater, Vthe layer 'will 'be correspdndnglyheavier.

'On-the 'drawings lI haye indicated 'the ldieti'f the current/flow frfnthe battery and" 'choke by m11 line' ari-ens' and the 'currents from menumerator m by ect-redire@ 'arrows and it is thus seenvthat forconditions liifhen the niedulater circuit is closed "that 'the currentsfrom the sources mand e will and' r0- fgether' inthe chokes andv"c'ppcrse yeach other ifn'the'lfrequency cli'angers et. i

Having thus described my invention, vvrihat Wireless systems comprisingseries connected frequency changers and keying chokes Which includesimpressing a saturating direct current on said frequency changers andkeying chokes, and simultaneously and oppositely j'changing thesaturation of said frequency changers and keying chkes.

2. in combination, a frequency changer and' series Vconnected keyingchoke, and means forV simultaneously and oppositely lchanging theVmagnetic saturation of said frequency changer and keying choke.

In combination, a frequency changer provided With Va copper -core andthin outer magnetic material, a keying choke provided with a copper coreand outer magnetic layer, a source of direct current traversing said'frequency vchanger and keying choke, and means for simultaneously andoppositely changing the magnetic 'saturation ofthe 'outer magneticlayerof both said frequency changer and keying choke. l

4. In combination, a plurality lof frequency changers and a plurality ofkeying chokes, each of said frequency changers being series connectedwith respect to a keying choke and each frequency changer and eeriesconnected keying choke being parallel connected v'vith respect to theother frequency 'changers andL keying chokes, means 'for introducing vasaturating direct current into said system at "diagonally oppositepoints, and means" for s'imultaneously and oppositely changi'lg the'saturation of said frequency changers fand keying choke's due to saidsaturating direct current. n ,Y

5. In combinati-on, a plurality of frequency changer elements 'and vaplurality' of keying choke elements, all o f sai'delenents beingarranged to form a ,/Vheatstone bridge strnctur'e wherein 'the frequencychan-ger elements are arranged in opposite legs' and a keying chokevelement is in the 'leg adja'cei'lt e'ac'hfof said frequeny changerelements,"rnean`s for introducingV a direct "current "on one ldiagonalof said bri vge, said current being adapted 'to influence the magnetic1saturatim of saidel'ements, and means in the second diagonal 'of saidbridge for further controlling the magnetic 'saturation/of saidelements.

6. The combination claimed in claim 5 wherein 1the controlling means. in`the second diagonal of said bridge is adapted 'to Ysimultaneously and`oppoeitely influence the magnetic saturation of `said frequency changerand keying 'choke elements. ,y

7. The combination claimed in claim wherein 'said triage is arrangedegress a high frequency :System 'and `Said variation saturation of said'elements lis adapted to influence said high frequency system.

8. In cornbnationia plaralityjor frequency changer elements, a pluralityof keying choke elements, all of sain elements being 'arrangedalternately te rcrfn the four legs 'or a Wheatstone bridge formationwhereby a frequency changer element. and a keying choke element isseries connected Withrespect to each other and each frequency changerelement and `series connected keying choke is parallel connected Withrespect to a like frequency changer and series connected keying chokeelement, a direct current source in one diagonal of said bridge, saiddirect curernt being adapted to influence the magnetic saturation ofsaid elements, a second direct current in the opposite diagonal of saidbridge, said last named direct current being adapted to simultaneouslyand oppositely Vary the magnetic saturation produced in said elements bysaid first named current, and a high frequency circuit adapted forcontrol by said bridge formation structure.

\ 9. In a high frequency Wireless system, a means to increasesensitivity which comprises,

y a plurality of frequency changer and keying choke elements alternatelyconnected With respect to each other whereby they are adapted to form aWheatstone bridge arrangement, a source of current in one diagonal ofsaid bridge, said current being adapted to flow through both saidfrequency changer and keying choke elements and influence the magneticsaturation of the same, and a source of modulating current in the seconddiagonal of said bridge, said modulating current being adapted tosimultaneously and oppositely vary the saturating current in saidelements.

MENDEL OSNOS.

